Differential drive for automotive vehicles



Feb. 1, K66 R. L. HOLLOWAY DIFFERENTIAL DRIVE FOR AUTOMOTIVE VEHICLES 5Sheets-Sheet 1 Original Filed June '7, 1960 INVEINTOR RO@ER,T I...HQLLOWAY Feb. 1, 1966 R. 1.. HOLLOWAY DIFFERENTIAL DRIVE FOR AUTOMOTIVEVEHICLES 3 Sheets-Sheet 2 Original Filed June 7. 1960 INVENTOR ROERT L.HO LLOWAY Feb; i, i% L. HOLLOWAY DIFFERENTIAL DRIVE FOR AUTOMOTIVEVEHICLES 3 Sheets-Sheet 5 Original Filed June 7, 1960 INVENTOR ROBERT L.HOLLOWAY United States Patent 3,232,369 DIFFERENTIAL DRIVE FORAUTOMOTIVE VEHICLES Robert L. Holloway, Snyder, N.Y., assignor toAmerican Machine & Foundry Company, a corporation of New Jersey Originalapplication June 7, 1960, Ser. No. 34,506, new Patent No. 3,16),597,dated Feb. 16, 1965. Divided and this application June 1, 1964, Ser. No.379,060 2 Ciaims. (Cl. 180-76) This is a division of copendingapplication Serial No. 34,506, filed June 7, 1960, now Patent No.3,169,597.

This invention relates generally to small automotive vehicles known ascarts, and more popularly as Go- Carts. More specifically, the inventionrelates to overrunning clutch drives and brakes for such vehicles.

Vehicles of this type generally have a rear wheel drive. In the pastthis drive has been of several kinds. In one, separate motors havedriven each wheel. In another, only one wheel has been driven and inothers both wheels have been driven by a live axle by one or moreengines.

In going around curves, where the outside wheel must travel farther thanthe inside wheel while the cart is turning, it is important that meansbe provided to ensure that the outside wheel travels faster than theinside wheel, to avoid unncessary drag on the vehicle. Commondifferential drives accomplish this as in automotive vehicles, but insuch cases where one wheel spins, all traction is lost. While modernautomobiles on the market today feature rear wheels anti-spinningdrives, they are complex and costly and would not be either feasible orpracticable for the simple low cost Go-Cart field.

It is therefore an object of this invention to provide an improvedracing cart having a one way clutch drive for the rear wheels which hasfew components, is sturdy, easily assembled, reliable in operation andlow in cost of manufacture.

A further object of the present invention is to provide a rear axleassembly having limited overrun clutches interposed between a drivenshaft and the rear driving wheels of a vehicle.

Other objects and features of the invention will appear as thedescription of the particular embodiment selected to illustrate theinvention progresses. In the accompanying drawings, which form a part ofthis specification, like characters of reference have been applied tocorresponding parts throughout the several views which make up thedrawings.

FIG. 1: is a perspective view of a Go-Cart which is adaptable for usewith the present invention.

FIG/Zis a sectional schematic arrangement of one embodiment of the drivesystem of the invention.

FIG. 3 is a fragmentary sectional View of one preferred designarrangement in accordance with the schematic of FIG. 2. and, employingso called scrubber brakes.

FIGQ4 is a sectional view showing'the drive of the invention embodied ina jack shaft arrangement allowing a double speed reduction and a choiceof brake arrangement.

Like reference characters identify like parts in the above views.

Broadly construed, the present invention consists in providing one wayclutches between a drive sprocket and each drive wheel of a vehicle suchas aGo-Cart. Such clutches, unlike brakes, permit free movement in thereverse direction.

A vehicle on which the drive of the invention may be mounted is shown inFIGURE 1. This vehicle consists ofaframe having front wheels 12 and 14,mounted thereon in any suitable manner, as on a front axle 16.

3,232,369 Patented Feb. 1, 1966 The frame has a rearwardly inclinedportion 18 forming a back rest for the driver, and rails 20, suitablyelevated from the ground to a plane above tubular frame 10 so as to formguards. Welded to frame 10 is forwardly inclined U-frame 22 supportingsteering column 24, which is inclined upwardly and rearwardly, and has asteering wheel 26 secured to its free end.

The other end of column 24 is connected to a tie rod 28 for turning thefront wheels. A front tubular bumper 30 is secured to the front axle 16.An engine 32 is secured to the vehicle by means of bracket 44, which issecured to the rear axle housing 54 and frame member 49. Tubular members34 and 36 are attached to rear axle housing 54 and back member 18 toprovide a rear support.

The engine is preferably disposed in offset relation to the medial axisof the frame, but may be placed elsewhere, if desired. Suitably thisengine may be of the air cooled type. Mounted above the engine is fueltank 47. The crankshaft of the engine has a sprocket and centrifugalclutch keyed thereon, and is connected by means of an endless chain to asprocket 48 adjacent one of the rear wheels. The vehicle is alsoequipped with starting means (not shown) which may be of theconventional recoil starter type commonly employed on air cooled motors.

Foot brake pedal 50 is mounted on the front end of the vehicle, andbraking action is communicated to the rear wheels through brake rod 53mounted along the tubular frame. The front end of the rod is secured tothe lever of the brake pedal. The other end is fastened to a suitablelever (not shown) on brake shaft 57 Which is mounted transversely ofchassis 10 and having a lever extension 40 on which is mounted aremovable tire engaging member 59.

It has been found that when smooth racing tires are employed,conventional flat tire engaging members are sometimes ineffectivebecause stone, sand, etc., find their way between the tire and the tireengaging member, and thereby act as anti-friction bearings in effect.

I have found that the tire engaging member 59 shown in FIGURE 3 verysatisfactorily overcomes this deficiency. The tire engaging member 59shown in FIG- URES 1 and 3 is made from a standard die spring which isof such a length that when the washer 11 and the ca screw 13 are securedto the lever extension 40 it will be under compression between thewasher and the right angle bend of the extension 40, thus preventing itfrom rotating.

It has been found that the spirals of the spring 5? provide a selfcleaning action and no anti-friction effect is encountered because ofthe sand particles mentioned above.

When conventional knobby tires are employed then the spring member 59may be removed and replaced by a conventional smooth flat plate (notshown) which brakes against the tire being stopped, the treads of whichthen provide the self cleaning action.

The drive of the present invention is illustrated in detail on FIGURE 3.The member 54 is a tubular rear axle housing supported by frame members49 and terminating in stationary bearing housing 61. As shown, sprocket48 is fixedly connected to a sleeve 52 in any suitable manner such as bywelding or by shrinking. Sleeve 52 is keyed on axle 54A by means of key56, so that axle 54A may be rotated by the movement of sprocket 48 whenthe same is turned by motion transferred thereto from engine 32. Sleeve52 has a cup-shaped end 58 abutting clutch housing 60, which has aflange 62 secured for rotation with another flange 64 on wheel bearinghousing 66. Housings 66 and 60 are freely journaled on axle 54A, throughball bearings 63 and 65. Housing and sleeve 52 are provided with alignedaxial recesses within which is received helical right hand woundprehensile spring 68. This spring has an internal diameter larger thanthat of axle 54A, over which it is freely mounted. The spring may be ofany effective clutching configuration, so that when it is not subjectedto any stress, it has an internal diameter slightly larger than theinternal diameter of the recesses. In operation all torque exerted onthe spring originates from the motion of the axle or from motion of thewheel bearing housing. In turn the spring bears against the cylindricalwalls of the recesses. When sprocket 48 is rotated, spring 68 expands toimpart drive from housing 58 to housing 60, thereby imparting drivingmotion to the wheel. When it is necessary for the wheel to rotate fasterthan sprocket 48, the spring 68 contracts to allow forward slipping ineither housing 58 or housing 60.

On the opposite end of axle 54A near the other rear wheel is mounted asimilar arrangement as that above described with the exception that nosprocket is mounted on its sleeve unless the vehicle has a second enginemounted thereon, which would requre such a sprocket. In thisarrangement, a left hand wound prehensile spring, as opposed to theright hand wound spring, is also used to impart a driving motion to thewheel bearing housing and hence to the wheel.

In the embodiments above described, the overrunning clutches have beenpositioned on oppoiste ends of the axle rod. It will be appreciatedhowever, that the present invention need not be restricted to thatprecise positioning of elements. For example, the two clutches may beinstead mounted on split axles on either side of the sprocket 94.

For example, in the embodiment of the invention shown on FIGURE 4,clutches are provided in association with a jack shaft from which motionis transmitted to the rear wheels. FIGURE 4 is a rear view of thisembodiment. This view is shown rotated to show more clearly thearrangement of the component parts, since the jack shaft assembly andthe wheel shaft assembly do not lie on the same plane.

In FIGURE 4, the jack shaft assembly comprises a central sprocket 94fixedly secured to sprocket sleeve 96 by suitable means such as weldingor upsetting. An endless chain A connects sprocket 94 to engine drivesprocket B. The central part of sleeve 96 has a bearing 97 in which fitthe abutting ends of jack shafts 114 and 115, in shaft housings 93 and95. Sprocket sleeve 96 has two cup-shaped recesses 98 and 100 on eitherside of the sprocket 94. These recesses open away from the sprocket andcommunicate with oppositely facing recesses 102 and 104 in tubularsleeves 106 and 108 to form spring housings.

Two helical right hand and left hand wound springs and 122 fit inrecesses 98 and 102, and 100 and 104, respectively. The outer surfacesof the springs bear against the internal surfaces of the recesses whendriving motion is imparted to the sprocket and transmit this motion tosleeves 106 and 108. Pins 117 secure sleeves 106 and 108 to theirrespective shafts 114 and 115.

Spacers 111 and 113 separate these sleeves 106 and 108 from bearings 120and 121 in which the jack shafts 114 and 115 rotate. Brackets 123 andclamp rods 119 secure the two housings 93 and 95 together. The housings93 and 95 are secured to the cart frame by suitable means (not shown)such as welding or bolting.

At the other end of each housing are positioned bearings 124 in whichthe jack shafts 114 and 115 rotate. Mounted on the jack shafts 114 and115 are collars 118 and sprockets 128 fixedly secured on the jack shafts114 and 115.

On a different plane on the cart chassis from the above assembly ispositioned the rear axle assembly. This as- 'sembly comprises rear axle130 in which is mounted wheel shaft 132. Brake drums 134 which arewelded to sprockets 136 are freely journaled on the wheel shaft 132.Endless chains 138 connect sprockets 136 and 128. Suitable wheel clamps140 secure the wheels to the rear axle sprockets by means of studs andbolts (not shown).

During normal operation of the above described version of the invention,driving motion imparted to central sprocket 94 is transferred by meansof the helical springs to the jack shafts and the two sprockets thereon.Since these two sprockets are operatively connected to the wheelspockets on the rear axle the latter will also be driven. When either ofthe rear wheels must rotate faster than the other; that is, faster thanthe speed at which it is turned, it will pull on its corerspondingsprocket on the jack shaft causIng the same to slip within its clutchhousing. In turn, the clutch housing member keyed on the shaft will slipover the spring surface.

It will also be appreciated instead of employing a jack shaft drive asshown in FIGURE 4, it is also possible to mount the driven rear wheelsdirectly upon the extremities of jack shafts 114 and 115 in place ofsprockets 128.

It has been found desirable in some instances to employ jack shafts asshown in FIGURE 4, to provide not only a reduction from engine speed towheels speed, but also to permit the easy use of internal expandingbrakes instead of the scrubber brakes shown in FIGURES l and 3.

In the foregoing description the term carting is frequently written inthe trade as karting but for consistency, I have spelled this ascarting.

It will also be appreciated that while this invention has filled a needin the carting field, it can also be advantageously employed on avariety of vehicles, as far example, golf carts, lawn mowers, andsimilar vehicles,

The invention hereinabove described may therefore be varied inconstruction within the scope of the claims, for the particular deviceselected to illustrate the invention is but one of many possibleembodiments of the same. The invention, therefore, is not to berestricted to the precise details of the structure shown and described.

What is claimed is:

1. In a vehicle having a chassis, driving means and steering means, aclutch drive comprising a sprocket sleeve having internal recesses ateach end thereof, a sprocket on said sleeve driven by said drivingmeans, a pair of jack shafts rotatably mounted in said sprocket sleevein endwise abutting relationship, each jack shaft having a sleeve memberfixedly mounted thereon, said jack shaft sleeve members, each having aninternal recess abuttingly aligned with one of said recesses in saidsprocket sleeve forming therewith a clutch chamber, prehensile springsmounted in said chambers about said jack shafts and operativelyconnected with said sprocket sleeve, said jack shaft sleeves beingdriven when said springs are rotated in a direction to expand saidsprings and means mounted on the ends of each jack shaft fortransmitting motion to a ground engaging wheel.

2. In a vehicle having a chassis, driving means and stering means, aclutch drive comprising a sprocket sleeve having internal recesses ateach end thereof, a sprocket on said sleeve driven by said drivingmeans, a pair of jack shafts rotatably mounted in said sprocket sleevein endwise abutting relationship, each jack shaft having a sleeve memberfixedly mounted thereon, said jack shaft sleeve members, each having aninternal recess abuttingly aligned with one of said recesses in saidsprocket sleeve forming therewith a clutch chamber, prehensile springsmounted in said chambers about said jack shafts and operativelyconnected with said sprocket sleeve, said jack shaft sleeves beingdriven when said springs are rotated in a direction to expand saidsprings, a sprocket mounted on the ends of each jack shaft and a rearaxle assembly comprising an axle rod, brake drums freely mounted 5 6 onsaid rod, sprockets secured to said drums, Wheels fas- 2,927,480 3/1960Schweickart 18076 X tened to said drum sprockets and endless chainsdrivingly 3,026,739 3/ 1962 Hungerford. connecting said drum sprocketswith corresponding jack 3,040,855 6/1962 Chiilson 19250 Shaft sprockets-FOREIGN PATENTS References Cited by the Examiner 5 g ja rea' r1 am.UNITED STATES PATENTS 586,604 12/1953 Italy 659,222 10/1900 Foster180-76 849 474 4/1907 1 BENJAMIN HERSH, Przmary Exanzzner. 930,5518/1909 Lloyd 18070 X 10 KENNETH H, BETTS, MILTON BUCHLER,

1,006,500 10/1911 Peterson. Examiners.

1. IN A VEHICLE HAVING A CHASSIS, DRIVING MEANS AND STEERING MEANS, ACLUTCH DRIVE COMPRISING A SPROCKET SLEEVE HAVING INTERNAL RECESSES ATEACH END THEREOF, A SPROCKET ON SAID SLEEVE DRIVEN BY SAID DRIVINGMEANS, A PAIR OF JACK SHAFTS ROTATABLY MOUNTED IN SAID SPROCKET SLEEVEIN ENDWISE ABUTTING RELATIONSHIP, EACH JACK SHAFT HAVING A SLEEVE MEMBERFIXEDLY MOUNTED THEREON, SAID JACK SHAFT SLEEVE MEMBERS, EACH HAVING ANINTERNAL RECESS ABUTTINGLY ALIGNED WITH ONE OF SAID RECESSES IN SAIDSPROCKET SLEEVE FORMING THEREWITH A CLUTCH CHAMBER, PREHENSILE SPRINGSMOUNTED IN SAID CHAMBERS ABOUT SAID JACK SHAFTS AND OPERATIVELYCONNECTED WITH SAID SPROCKET SLEEVE, SAID JACK SHAFT SLEEVES BEINGDRIVEN WHEN SAID SPRINGS ARE ROTATED IN A DIRECTION TO EXPAND ANDSPRINGS AND MEANS MOUNTED ON THE ENDS OF EACH JACK SHAFT FORTRANSMITTING MOTION TO A GROUND ENGAGING WHEEL.